1. Field of the Invention
The present general inventive concept relates to a karaoke system, and more particularly, to a vocal canceling apparatus and method of canceling a vocal component in a karaoke system.
2. Description of the Related Art
Generally, a karaoke system uses as an accompaniment, in which an audio signal is output from an audio device, such as a cassette player, a compact disc player or a tuner, and in which only a human vocal component is canceled. Most vocal components exist in a frequency band of 200 Hz to 4 kHz in the audio signal. A vocal signal is a single signal, that is, a mono signal, in an audio system. A music signal including sound of musical instruments is separated into a left channel and a right channel. Accordingly, except for the mono signal, waveforms of the audio signal input to a left channel terminal and the audio signal input to a right channel terminal are different to each other. Therefore, if the audio signal input to the left channel is subtracted from the audio signal input to the right channel, the audio signal in which the vocal signal is canceled can be generated. Generally, in a method of canceling a vocal component in a stereo music file, a difference between the left and right channels is obtained to cancel the vocal component since the vocal component, that is, voice of a singer, is located at a center channel of the audio signal.
U.S. Pat. No. 6,690,799 B1 discloses a ‘stereo signal processing apparatus’ relating to a vocal canceling circuit.
FIG. 1 is a block diagram illustrating a conventional vocal canceling apparatus. Referring to FIG. 1, right channel filter units 121 and 122 extract a low frequency signal and a high frequency signal from a right channel signal Rin. Left channel filter units 111 and 112 extract a low frequency signal and a high frequency signal from a left channel signal Lin. A subtraction unit 131 generates a vocal canceling signal by subtracting the right channel signal Rin from the left channel signal Lin. A left addition unit 113 generates a left channel output signal Lout by adding the low frequency signal and high frequency signal of a left channel from the left channel filter units 111 and 112 and the vocal canceling signal from the subtraction unit 131. A right addition unit 123 generates a right channel output signal Rout by adding the low frequency signal and high frequency signal of the right channel from the right channel filter units 121 and 122 and the vocal canceling signal from the subtraction unit 131.
Accordingly, the vocal canceling circuit of FIG. 1 adds a low frequency component and a high frequency component to a signal obtained according to a difference between the two channel signals. However, there is a drawback that cut off frequencies of a low frequency pass filter and a high frequency pass filter should always be accurately set with respect to a sound source. Also, when a signal of the frequency band of 200 Hz to 4 kHz to which human ears are sensitive becomes a mono signal, the signal outputs a very hard and dry sound compared to the original sound.